1. Field of the Invention
The present invention relates to a pad type coordinate input apparatus, and in particular relates to a coordinate input apparatus operable with both of a conductor such as a finger and a non-conductor such as a pen.
2. Description of the Related Art
As a pointing device for use in a personal computer, a pad type input apparatus is adopted, and it is specifically used for a number of note-type computers. In the type of input apparatus, an operating plane is formed of a planer sheet, and by operating the sheet surface with a finger, etc., coordinate data, in which a mouse-cursor displayed on a screen is moved in the desired direction, for example, can be inputted.
As detecting means of a conventional input apparatus, there are a capacitive type and a pressure-sensing type. The capacitive type detects the coordinates by measuring changes in capacitance while the pressure-sensing type detects the coordinates by measuring changes in voltage. Also, an input apparatus operable with both of a conductor such as a finger and a non-conductor such as a pen by using pressure-sensing type detecting means is commercially available.
However, when the operation with any one of a finger and a pen is to be achieved, the above-mentioned pressure-sensing type input apparatus has low detection sensitivity when operating it with a finger, etc., so that a mouse-cursor cannot be moved to a desired position, thereby impairing the sense of operating touch.
Therefore, an input apparatus having both of a capacitive type input section and a pressure-sensing type input section incorporated thereinto is proposed. However, although the sense of operating touch is not impaired, when electrically connecting from substrates in the capacitive and pressure-sensing sides to the side of a circuit board, the respective lead lines from the capacitive and pressure-sensing substrates to the outside have to be formed so as to insert them into insertion plugs formed in the circuit board, thereby increasing the apparatus in size, and the thickness thereof is further difficult to be reduced.
The present invention is made so as to solve the above-described problems, and it is an object of the present invention to provide an input apparatus operable without impairment of the sense of operating touch even with any one of a conductor such as a finger and a non-conductor such as a pen, and further capable of reducing the apparatus in size and thickness.
In accordance with the present invention, there is provided a coordinate input apparatus comprising: an electrostatic capacitive detection section for detecting coordinates by operating the electrostatic capacitive detection section with an indicator so as to change the electrostatic capacitance between an X electrode and an Y electrode, which are arranged so as to oppose each other via an insulating layer interposed therebetween; and a pressure-sensing detection section having a resistor and a conductor arranged so as to oppose the resistor, the pressure-sensing detection section detecting coordinates based on the resistance of the resistor at a contact point between the resistor and the conductor when being operated with a predetermined pressure, wherein the electrostatic capacitive detection section is deposited on the operating surface side of the pressure-sensing detection section, wherein the electrostatic capacitive detection section is flexible and is capable of being pressed against the pressure-sensing detection section, and wherein the pressure-sensing detection section comprises a high resistance resistor and a low resistance resistor arranged around the high resistance resistor, a voltage being applied alternately between low resistance resistor portions opposing in an X direction and between low resistance resistor portions opposing in an Y direction so that the coordinates are detected based on a voltage detected between the low resistance resistor and the conductor by causing the conductor to make contact with the high resistance resistor.
As described above, when the low resistance resistors are arranged around the high resistance resistor and the low resistance resistors are used as electrodes opposing in the X direction and the Y direction, changes in resistances in the X direction and the Y direction can be detected with high accuracy and without interference with each other when the high resistance resistor makes contact with the conductor.
It is preferable that a coordinate input apparatus further comprise a substrate arranged in the pressure-sensing detection section opposite to the electrostatic capacitive detection section, the substrate having through-holes penetrating from one face of the substrate toward the other face thereof, the through-hole penetrating through both the electrostatic capacitive detection section and the pressure-sensing detection section so that the X and Y electrodes of the electrostatic capacitive detection section are each connected to the substrate via the through-hole by filling the through-hole with a conductive material.
Preferably, a coordinate input apparatus further comprises a substrate arranged in the pressure-sensing detection section opposite to the electrostatic capacitive detection section, the substrate having through-holes penetrating from one face of the substrate toward the other face thereof, the through-hole penetrating through both the electrostatic capacitive detection section and the pressure-sensing detection section so that the low resistance resistor and the conductor of the pressure-sensing detection section are each connected to the substrate via the through-hole by filling the through-hole with a conductive material.
In this case, on the backside of the substrate, circuit elements for activating the pressure-sensing detection section and/or the electrostatic capacitive detection section are mounted, so that the through-holes and the circuit elements are connected via a circuit pattern formed on the backside of the substrate.
Owing to the above structure, it is not necessary that a lead portion be provided outside for any one of the pressure-sensing detection section and the electrostatic capacitive detection section, resulting in miniaturization of the apparatus and reduction in thickness thereof as well. Furthermore, the number of parts can be reduced, resulting in cost reduction.
Also, the electrostatic capacitive detection section may preferably comprise a face-sheet arranged on the operating face side of the electrostatic capacitive detection section via an insulator disposed therebetween.
For example, on the face of the electrostatic capacitive detection section, an insulator made of a resist film is printed and the face-sheet is fixed thereto via an adhesive.